WASHINGTON — The Food and Drug Administration found substantial levels of a worrisome class of nonstick, stain-resistant industrial compounds in some grocery store meats and seafood and in off-the-shelf chocolate cake, according to FDA researchers.

The FDA's food-test results are likely to heighten complaints by states and public health groups that President Donald Trump's administration is not acting fast enough or firmly enough to start regulating the manmade compounds.

A federal toxicology report last year cited links between high levels of the compounds in people's blood and health problems, but said it was not certain the nonstick compounds were the cause.

The levels in nearly half of the meat and fish tested were two or more times over the only currently existing federal advisory level for any kind of the widely used manmade compounds, which are called per- and polyfluoroalykyl substances, or PFAS.

The level in the chocolate cake was higher: more than 250 times the only federal guidelines, which are for some PFAS in drinking water.

Food and Drug Administration spokeswoman Tara Rabin said Monday that the agency thought the contamination was "not likely to be a human health concern," even though the tests exceeded the sole existing federal PFAS recommendations for drinking water.

As a handful of PFAS contaminations of food emerge around the country, authorities have deemed some a health concern but not others. The agency considers each discovery of the compound in food case by case, including the kind of food, levels of contamination, frequency of consumption and latest scientific information, Rabin said.

There are nearly 5,000 varieties of PFAS, which DuPont created in 1938 and first put into use for nonstick cookware. Industries use them in countless consumer items — food packaging, carpets and couches, dental floss and outdoor gear — to repeal grease, water and stains.

The chemicals also are found in firefighting foam, which the Defense department calls irreplaceable in suppressing jet-fuel fires. Especially around military bases and PFAS facilities, decades of use have built up levels in water, soil and some treated sewage sludge used to fertilize non-organic food crops and feed for livestock.

They've been a topic of congressional hearings, state legislation and intense federal and state scrutiny over the past two years.

Last year's federal toxicology review concluded the compounds are more dangerous than previously thought, saying consistent studies of exposed people "suggest associations" with some kinds of cancers, liver problems, low birth weight and other issues.

The compounds have been dubbed "forever chemicals" because they take thousands of years to degrade, and because some accumulate in people's bodies.

The Environmental Protection Agency earlier established a nonbinding health threshold of 70 parts per trillion for two-phased out forms of the contaminant in drinking water.

The EPA has said it would consider setting mandatory limits instead after the toxicology report and after federally mandated PFAS testing of water systems found contamination. The administration has called dealing with PFAS a "potential public relations nightmare" and a "national priority."

"I know there are people who would like us to move faster" on PFAS, EPA Administrator Andrew Wheeler said Monday at the National Press Club. "We are addressing this much faster than the agency has ever done for a chemical like this."

Impatient for federal action, several states have moved to regulate the chemicals on their own, including setting standards for groundwater or drinking water.

PFOS — already phased out of production in the U.S. as a health concern — turned up at levels ranging from 134 parts per trillion to 865 parts per trillion in tilapia, chicken, turkey, beef, cod, salmon, shrimp, lamb, catfish and hot dogs. Chocolate cake tested at 17,640 parts per trillion of a kind of PFAS called PFPeA.

The FDA presentation also disclosed PFAS findings — one spiking over 1,000 parts per trillion — in leafy green vegetables grown within 10 miles (16 kilometers) of an unspecified eastern U.S. PFAS plant and sold at a farmer's market.

And it previewed test levels for a previously reported instance of PFAS contamination of the food supply in the feed and milk at a dairy near an Air Force base in New Mexico. The FDA called the milk contamination a health concern.

FDA researchers discussed the results at a conference by the Society of Environmental Toxicology and Chemistry last week in Finland. The Environmental Defense Fund and the Environmental Working Group obtained the FDA presentation and provided it to The Associated Press.

"What this calls for is additional research to determine how widespread this contamination is and how high the levels are," said Linda Birnbaum, director of the National Institute of Environmental Health Sciences, in an interview. "We have to look at total human exposure — not just what's in the water or what's in the food ... or not just dust. We need to look at the sum totals of what the exposures are."

"Drinking one glass of contaminated water is unlikely to be associated with health risks, as is eating one slice of contaminated chocolate cake," said Jamie DeWitt, a toxicologist at East Carolina University who studies PFAS. "Individually, each item is unlikely to be a huge problem, but collectively and over a lifetime, that may be a different story."

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Flesher reported from Traverse City, Michigan, and Casey from Concord, New Hampshire.